Not completely. This has been entered into the SE bug tracking database as bug #2714.
IPv6 is enabled by default in both Vista and Longhorn.
Evidence for this is seen in the
C:\Windows\System 32\drivers\etc\hosts file.
You will see an entry of ::1 which resolves to localhost.
You can request http://localhost/servlet/TestServlet to see the value
that's returned by request.getRemoteAddr().
You'll see that that servlet runs just fine.
You'll see that the value for the remoteAddr is displayed in IPv6 format 0:0:0:0:0:0:0:1
If you were to request the SE Admin UI instead, here is what happens:
The SE admin UI compares the remoteAddr value (which is the IP of client/browser) to the configured allowedIPs value to decide if the client should be allowed to access the SE admin UI.
The algorithm that the SE 5 admin UI uses to ensure that remoteAddr meets the
"Allowed IPs" setting is not equipped to handle IPv6 addresses.
So it ends up deciding that the client should not be allowed to login to the admin UI.
One workaround is to use some other hostname besides localhost when accessing the SE admin UI.
For example, 127.0.0.1 will work.
Another workaround is to edit the hosts file, to remove or comment out the ::1 entry. Then localhost would work (after a browser restart).
Another issue that can occur when SE 5 is being used in an IPv6-enabled environment is
that SE's implementation of Request.getRemoteHost() returns an invalid value.
A servlet or JSP which runs, and does not need those values (the remoteAddr or the remoteHost)
should continue to run just fine.
Even if the client is on an IPv6 machine.
It depends on what you are requesting... whether or not it needs those values to be correct.
Note: SE 6 does support IPv6 completely